Columbus Audubon Web Extras    Christmas Bird Count Reveals Local Trends by Rob Thorn You've finally gotten inside and warmed up your fingers after a cold but exhilarating Christmas Bird Count.  You confer with your team leader, matching totals and swapping stories, before leaving for home.  But somewhere in your mind, you've probably stopped and thought, 'what do all these numbers mean?'  For what can we use Christmas Count data?  As a compiler, I've been particularly prey to these thoughts, and I've started to see some ways the count information can be and is used.  Some of them are unsurprising and expected, but others can surprise you.  I've included a table of the last 10 years of Columbus CBC data, so that you can see for yourself the uses that I will suggest, and perhaps some that I haven't noticed yet. Long-term Monitoring  When a count has pushed past 12-15 years, you now have a long-term record for early winter birds for that area.  In Columbus, we have 32 years of 'official' counts (submitted to National Audubon), with perhaps 20 years of 'unofficial' counts before that time, so we have a huge database.  (If you wish to see all of the official counts, go to the CBC homepage run by National Audubon, at http://www.audubon.org/bird/cbc).  This means that the Columbus CBC started back when Columbus was a mid-sized city.  Looking at early maps of the count reinforces that notion.  Minerva Park was the edge of the suburbs back then, and most of the southern portions of the count circle, stretching from South High Street east through Groveport to Reynoldsburg, were completely rural. That's just not the case anymore, though.  Columbus is now awash in suburban-style development, and our CBC circle is now very developed.  How is that reflected in birdlife?  Many open country birds just aren't here in any significant numbers any more.  Northern Harriers were fairly regular through the late '80s, but then became scarce afterwards.  Field Sparrows averaged 6-8 individuals per count through the late '70s, but have declined now to the point where one a year is optimistic.  Savannah Sparrows have disappeared altogether.  Eastern Meadowlarks were regular during the same time interval, but dropped off the count in the early '80s, to be seen only occasionally after that.  Both grackles and cowbirds were extremely common through the 1980s, but then dwindled down to rarity.   It doesn't take much thought to realize that these are all largely rural birds that have been displaced as their favored fields have sprouted a final crop of houses. Some supposed victims of suburbanization don't quite seem that way when viewed through the lens of the CBC.  Red-headed woodpeckers, a personal favorite, is a case in point.  While they were common during the 1950s-60s, they've been only sporadic since the early 70s.  They favored open oak woodlands, probably the rarest habitat in central Ohio now.  Generally they were seen for a few years whenever someone found a favored grove of oaks that hosted a few wintering individuals.  Recently, 'that grove' has been one on the eastern edge of Gahanna, so the last few counts have had them.  If they leave that grove, however, we'll miss them for a few years.  Another example of misperceptions is the Horned Lark, the classic bird of Ohio winter farmlands.  They have never been common close to Columbus, and have been irregular on the CBC since the late 60s.  Huge numbers show up whenever snowfalls force them along roadsides or into town.  We had nearly 200 on the snowy 2003 count, but if it doesn't snow, we'll be lucky to find a handful.  Raptors, Urbanization and West Nile Virus   As species at the top of the food chain, raptors have a privileged place in most types of bird censuses.  They're mostly large and fairly easy to spot (especially with the help of terrified smaller birds), and they hold a fascination for most nature-watchers.  Plus, with the advent of West Nile Virus, some of them have come under scrutiny as possible targets of this disease in North America. So how have Columbus raptors fared over the years of CBCs?  Our commonest raptors are Red-tailed Hawks, Cooper's Hawks, and Kestrels, and two of them have held up surprisingly well over the years.  The 41 Red-tails in '03 is among one of the highest totals ever, passed only by mid-40s seen from '95-'97. The large numbers of nests around Columbus, especially birds that have adapted to freeway margins, indicates that this species is adapting to our suburban environs. Cooper's Hawk numbers have varied widely, ranging recently from 34 (in '97) to 6 (in '00), but these numbers are usually well above the averages seen in the 70s and 80s (usually around 4-6).  The 22 seen in '03 falls well within the recent upsurge of this species.  They are clearly adapting to the burgeoning numbers of suburban feeders here.  Kestrels, however, have fared like other open-country birds, producing a steady slide from an average of 35-40 in the 1970s and 80s down to the low average of 7-10 in the last 5 years. It seems that West Nile Virus (WNV), a recent immigrant to Ohio, hasn't yet affected the above 3 species.  The targets it favors in the Midwest are owls and corvids.  Owls have never been numerous in Columbus.  The 4 Great Horned Owls seen in '03 are right on the species' average throughout the 70s - 90s, but such a small number may not indicate much change.  Barred owls have never been that numerous, with only 1-2 birds, usually in Blendon Woods or Blacklick Woods.  Blue jays have shown no pronounced declines over the past 10 years, but Crows are another story.  They were abundant from 1970-76 (ranging up to 4600+ birds in '72), but they dipped down to between 200-400 throughout the late 70s and 80s.  In the 90s they climbed again, peaking at 2200 birds in '97.  However the last 4 years have seen a slide down to the meager 113 birds found in '03.  Some of this has to do with the dynamics of roosts: the 90s totals were swollen by a huge roost in south Columbus near Corr Road.  This roost appears to have drastically declined, and whether it is a victim of WNV or some land-use change is unclear. Half-Hardy Birds and the Joys of Urban Birding  Columbus sits at the northern edge of many species' winter ranges.  Birds like Mockingbirds, Catbirds, Thrashers, Hermit Thrush, Eastern Bluebirds, Carolina Wrens, and some of the sparrows don't tolerate prolonged snow cover and low temperatures well, and have been dubbed the 'half-hardy' bird species.  We get many half-hardy species on the CBC, and their numbers have been increasing.  Many of them seem to take advantage of the slightly warmer temperatures and ornamental plantings in many Columbus neighborhoods and parks.  Even fairly hardy species like Starlings and Robins seem to be accumulating in Columbus in increasing numbers during the winter; just check the record totals of both on the '03 Count, or look at the big flocks swarming around your neighborhoods.  Some of the half-hardies may be becoming fully hardy as well.  Carolina Wren numbers have rebounded from the frigid winters of the late 70s, and are now very high, despite 2 cold winters in a row.  As I type this article, we have a wren working over our suet feeder, and our neighbors have chased wrens out of their garage and house.  These birds are evolving tricks to cope with Ohio winters, and the urban areas of Columbus are their laboratory.   Other birds may be pushing into the half-hardy category as well.  Pine Warblers were on the '01 Count and just missed the '02 Count, and an Orange-crowned Warbler was found in '03.  Hardly a year goes by now where the CBC doesn't produce some unusual vagrant or lingering species. This leads to an odd paradox.  I can spend a winter day at Kildeer Plains or Big Island and feel lucky if I see 100 birds of 20 species.  In order to get there, though, I'll drive through areas of Columbus and Delaware County that have many more species and individuals.  In fact, the urban areas of Ohio often have much higher concentrations of birds, probably due to their plantings and feeders.  It's no accident that Toledo and Cincinnati are among the top CBCs in Ohio in terms of species diversity, and that Columbus and Dayton lead their regions.   Urban areas may be the more interesting and diverse areas to bird during the winter, and I now spend most of my winter trips around Columbus. Quartering the Columbus Circle, Present and Future Part of the dynamics of a CBC is that each of them is squeezed into a 15 mile-diameter circle.  The Columbus circle is centered just southwest of Port of Columbus Airport, so it includes an area stretching from Griggs dam on the east, north to I-270, east to the village of Blacklick, and south to the northern edge of Groveport.  Like most CBCs, this circle is divided up into territories, and there are from 10 to 12 different territories in Columbus.  Territories are an artificial construction, however, and they live only so long as a committed organizer exists to run them.  For instance, the Olentangy-OSU territory, under the dogged leadership of Don Burton, has been chugging along for over 20 years.  On the other hand, a territory including Bexley, Whitehall, and the airport has been only sporadically covered in the last 10 years. As I've participated in and compiled the count, I've noticed four different areas of the circle, roughly corresponding to the edges of the four quarters of the circle, each with different strengths and peculiarities.  So let's take a quick tour of the four quarters of the Columbus Circle. The Olentangy-Scioto corridors  Usually covered by 4-5 different teams, this area includes OSU, Clintonville/Whetstone Park, Griggs dam, the Dublin Road-Hidden Lake quarries, Upper Arlington, and Grandview Heights.  The upland areas are grown-up suburbs with almost forest-like plantings in places, but the teams spend most of their time in the nearly continuous strip of undeveloped land and parks along the Scioto and Olentangy rivers.  For diversity of birds this area is superb, with many unusual species coming from along the Scioto corridor and the OSU Campus Area. The Blendon-Jefferson Uplands This area includes the highlands and ravines of Blendon Woods, nearby Gahanna, and Jefferson Township.  Each of these areas is covered by a separate party.  This area has retained a lot of woodland (especially Blendon Woods and tightly-zoned Jefferson Township) and produces good numbers of forest species.  A lot of woodpeckers, creepers, and forest raptors (Cooper's, Sharpie, Red-shouldered, and owls) come from this section. The Creeks Lowlands   Ranging from Reynoldsburg on the east to the Creeks Park on the west, this flat lowland is defined by 3 meandering creeks: Alum, Big Walnut, and Blacklick.  Until recently it was mostly farms with fields and woodlots, but it has rapidly suburbanized over the last 10-15 years.  Now only a few farms remain, mostly along the lower edges of Blacklick Creek.  Fortunately, the Creeks Park has saved a nice swath of this area from development.  This section is the last stronghold for open country species in the circle.  It also has a lot of small ponds that can attract waterfowl (if the ponds are not frozen).  Blacklick Woods and a few of the wooded Columbus city parks along the creeks add some woodland birds into the mix. The Greenlawn area Usually covered by 1-2 parties, this area includes the Greenlawn dam and Scioto River parks around it, as well as the cemetery and a host of old and new quarries south of these areas.  For rarities and waterbirds, this is the place to be.  Even in the coldest counts, this part of the Scioto rarely freezes, so it hosts many herons and waterfowl, often attracting unusual ducks.  The quarries and Jackson Park Wastewater treatment Plant south of Greenlawn can be exceptional for sparrows and edge birds, as well as waterfowl in those years when their ponds don't freeze.  The Green Lawn Cemetery with its conifer plantings is a magnet for unusual winter finches. If the Columbus Count circle has changed radically over the last 30 years, what might the next 30 hold?  Let's use the quarters and peer into our crystal balls.  The Olentangy and Scioto Corridors probably will not change much.  They may even get more accessible as Columbus extends its bike path to link various parklands along the Scioto up to Griggs dam.  The Blendon-Jefferson Highlands may see slow, steady development, so that some of its forest area might be eroded, but development in these suburbs has been much less dense than in areas of city of Columbus.   The southern quarters offer less sanguine prospects.  The Creeks Lowlands are still a major development frontier for Columbus, so most of the remaining farms will probably disappear here within 5-10 years.  The Greenlawn area has less development pressure due to its semi-industrial nature, but its future is also uncertain.  Many of the old quarries offer surprising wildlife oases close to urban Columbus, and one dreams that some of them might be fashioned into a wildlife reserve corridor along the Scioto.  Whoever writes this review in 2034 will probably say that the last 30 years radically transformed the Columbus CBC.  Let's hope and work to make sure it's for the better. Page updated 02/12/04 © Columbus Audubon 2004